The present invention relates generally to gas turbine engines, and more particularly to a seal arrangement of a gas turbine engine.
A gas turbine engine typically includes a high pressure spool, a combustion system and a low pressure spool disposed within an engine case to form a generally axial, serial flow path about the engine centerline. The high pressure spool includes a high pressure turbine, a high pressure shaft extending axially forward from the high pressure turbine, and a high pressure compressor connected to a forward end of the high pressure shaft. The low pressure spool includes a low pressure turbine, which is disposed downstream of the high pressure turbine, a low pressure shaft, which typically extends coaxially through the high pressure shaft, and a low pressure compressor connected to a forward end of the low pressure shaft, forward of the high pressure compressor. The combustion system is disposed between the high pressure compressor and the high pressure turbine and receives compressed air from the compressors and fuel provided by a fuel injection system. A combustion process is carried out within the combustion system to produce high energy gases to produce thrust and turn the high and low pressure turbines, which drive the compressors to sustain the combustion process.
Both the high and low pressure spools include alternating cascades of stators and rotors in order to work on the primary fluid in the flow path. Because the stators are stationary but the rotors rotate, bearings are necessary to permit the relative motion. Bearings can be situated in bearing compartments that provide oil to the moving parts for lubrication.
The combustion system heats the primary fluid in the flow path to very high temperatures, so both the high and low pressure turbines utilize cooling air from the high and/or low pressure compressors. This cooling air can be fed into a bearing compartment in order to cool and purge the bearing compartment of any stray oil that has leaked out. Because the boundaries of the bearing compartment can be formed by several components, seal arrangements are utilized between the components to control fluid flow.